This invention relates to a process for the production of a catalyst which contains on an inert, refractory support metallic copper, silver, gold, platinum or palladium in finely divided form and at least one metal of Group VIII of the Periodic System of Elements as active component.
Catalysts of this type may be produced by precipitating two or more metals in the form of oxidic compounds or other water-insoluble compounds onto the inert, refractory support from a suspension containing the inert support in suspension and the metals to be precipitated in the form of ions. The support thus loaded is separated off, calcined and reduced (U.S. Pat. No. 3,371,050).
A major disadvantage of this process lies in the fact that the active component is initially deposited on the support in the form of oxidic compounds which then have to be reduced. This reduction step is time-consuming and, in some cases, can only be carried out by very rigorous reduction methods if complete reduction to the metal is to be achieved. Another problem which applies in particular to catalysts containing several metals as active component lies in the fact that the oxidic compounds do not form mixed lattices that easily. This causes the formation of an inhomogeneous end product i.e. the alloy particles comprising both metals show considerable variations in composition from one particle to another.
The object of the present invention is readily to produce catalysts of the type mentioned at the beginning, the catalysts obtained containing the active component completely or largely in metallic form. It has surprisingly been found that this object can be achieved if at least one of the active components is deposited as a metal from the corresponding carbonyl, onto a precursor comprising the basis component in metallic form.